1DBIx::Class(3) User Contributed Perl Documentation DBIx::Class(3)
2
6 DBIx::Class - Extensible and flexible object <-> relational mapper.
7
9 See DBIx::Class::Manual::DocMap for an overview of the exhaustive
10 documentation. To get the most out of DBIx::Class with the least
11 confusion it is strongly recommended to read (at the very least) the
12 Manuals in the order presented there.
13
15 Due to the sheer size of its problem domain, DBIx::Class is a
16 relatively complex framework. After you start using DBIx::Class
17 questions will inevitably arise. If you are stuck with a problem or
18 have doubts about a particular approach do not hesitate to contact us
19 via any of the following options (the list is sorted by "fastest
20 response time"):
21 • RT Bug Tracker:
23 <https://rt.cpan.org/Public/Dist/Display.html?Name=DBIx-Class>
24 • Email: <mailto:bug-DBIx-Class@rt.cpan.org>
26 • Twitter:
28 <https://twitter.com/intent/tweet?text=%40ribasushi%20%23DBIC>
29
31 For the very impatient: DBIx::Class::Manual::QuickStart
32 This code in the next step can be generated automatically from an
34 existing database, see dbicdump from the distribution
35 "DBIx-Class-Schema-Loader".
36 Schema classes preparation
38 Create a schema class called MyApp/Schema.pm:
39 package MyApp::Schema;
41 use base qw/DBIx::Class::Schema/;
42 __PACKAGE__->load_namespaces();
44 1;
46 Create a result class to represent artists, who have many CDs, in
48 MyApp/Schema/Result/Artist.pm:
49 See DBIx::Class::ResultSource for docs on defining result classes.
51 package MyApp::Schema::Result::Artist;
53 use base qw/DBIx::Class::Core/;
54 __PACKAGE__->table('artist');
56 __PACKAGE__->add_columns(qw/ artistid name /);
57 __PACKAGE__->set_primary_key('artistid');
58 __PACKAGE__->has_many(cds => 'MyApp::Schema::Result::CD', 'artistid');
59 1;
61 A result class to represent a CD, which belongs to an artist, in
63 MyApp/Schema/Result/CD.pm:
64 package MyApp::Schema::Result::CD;
66 use base qw/DBIx::Class::Core/;
67 __PACKAGE__->load_components(qw/InflateColumn::DateTime/);
69 __PACKAGE__->table('cd');
70 __PACKAGE__->add_columns(qw/ cdid artistid title year /);
71 __PACKAGE__->set_primary_key('cdid');
72 __PACKAGE__->belongs_to(artist => 'MyApp::Schema::Result::Artist', 'artistid');
73 1;
75 API usage
77 Then you can use these classes in your application's code:
78 # Connect to your database.
80 use MyApp::Schema;
81 my $schema = MyApp::Schema->connect($dbi_dsn, $user, $pass, \%dbi_params);
82 # Query for all artists and put them in an array,
84 # or retrieve them as a result set object.
85 # $schema->resultset returns a DBIx::Class::ResultSet
86 my @all_artists = $schema->resultset('Artist')->all;
87 my $all_artists_rs = $schema->resultset('Artist');
88 # Output all artists names
90 # $artist here is a DBIx::Class::Row, which has accessors
91 # for all its columns. Rows are also subclasses of your Result class.
92 foreach $artist (@all_artists) {
93 print $artist->name, "\n";
94 }
95 # Create a result set to search for artists.
97 # This does not query the DB.
98 my $johns_rs = $schema->resultset('Artist')->search(
99 # Build your WHERE using an SQL::Abstract::Classic-compatible structure:
100 { name => { like => 'John%' } }
101 );
102 # Execute a joined query to get the cds.
104 my @all_john_cds = $johns_rs->search_related('cds')->all;
105 # Fetch the next available row.
107 my $first_john = $johns_rs->next;
108 # Specify ORDER BY on the query.
110 my $first_john_cds_by_title_rs = $first_john->cds(
111 undef,
112 { order_by => 'title' }
113 );
114 # Create a result set that will fetch the artist data
116 # at the same time as it fetches CDs, using only one query.
117 my $millennium_cds_rs = $schema->resultset('CD')->search(
118 { year => 2000 },
119 { prefetch => 'artist' }
120 );
121 my $cd = $millennium_cds_rs->next; # SELECT ... FROM cds JOIN artists ...
123 my $cd_artist_name = $cd->artist->name; # Already has the data so no 2nd query
124 # new() makes a Result object but doesn't insert it into the DB.
126 # create() is the same as new() then insert().
127 my $new_cd = $schema->resultset('CD')->new({ title => 'Spoon' });
128 $new_cd->artist($cd->artist);
129 $new_cd->insert; # Auto-increment primary key filled in after INSERT
130 $new_cd->title('Fork');
131 $schema->txn_do(sub { $new_cd->update }); # Runs the update in a transaction
133 # change the year of all the millennium CDs at once
135 $millennium_cds_rs->update({ year => 2002 });
136
138 This is an SQL to OO mapper with an object API inspired by Class::DBI
139 (with a compatibility layer as a springboard for porting) and a
140 resultset API that allows abstract encapsulation of database
141 operations. It aims to make representing queries in your code as perl-
142 ish as possible while still providing access to as many of the
143 capabilities of the database as possible, including retrieving related
144 records from multiple tables in a single query, "JOIN", "LEFT JOIN",
145 "COUNT", "DISTINCT", "GROUP BY", "ORDER BY" and "HAVING" support.
146 DBIx::Class can handle multi-column primary and foreign keys, complex
148 queries and database-level paging, and does its best to only query the
149 database in order to return something you've directly asked for. If a
150 resultset is used as an iterator it only fetches rows off the statement
151 handle as requested in order to minimise memory usage. It has auto-
152 increment support for SQLite, MySQL, PostgreSQL, Oracle, SQL Server and
153 DB2 and is known to be used in production on at least the first four,
154 and is fork- and thread-safe out of the box (although your DBD may not
155 be).
156 This project is still under rapid development, so large new features
158 may be marked experimental - such APIs are still usable but may have
159 edge bugs. Failing test cases are always welcome and point releases
160 are put out rapidly as bugs are found and fixed.
161 We do our best to maintain full backwards compatibility for published
163 APIs, since DBIx::Class is used in production in many organisations,
164 and even backwards incompatible changes to non-published APIs will be
165 fixed if they're reported and doing so doesn't cost the codebase
166 anything.
167 The test suite is quite substantial, and several developer releases are
169 generally made to CPAN before the branch for the next release is merged
170 back to trunk for a major release.
171
173 Contributions are always welcome, in all usable forms (we especially
174 welcome documentation improvements). The delivery methods include git-
175 or unified-diff formatted patches, GitHub pull requests, or plain bug
176 reports either via RT or the Mailing list. Do not hesitate to get in
177 touch with any further questions you may have.
178 This project is maintained in a git repository. The code and related
180 tools are accessible at the following locations:
181 • Current git repository: <https://github.com/Perl5/DBIx-Class>
183 • Travis-CI log:
185 <https://travis-ci.com/github/Perl5/DBIx-Class/branches>
186
188 Even though a large portion of the source appears to be written by just
189 a handful of people, this library continues to remain a collaborative
190 effort - perhaps one of the most successful such projects on CPAN
191 <http://cpan.org>. It is important to remember that ideas do not
192 always result in a direct code contribution, but deserve
193 acknowledgement just the same. Time and time again the seemingly most
194 insignificant questions and suggestions have been shown to catalyze
195 monumental improvements in consistency, accuracy and performance.
196 The canonical source of authors and their details is the AUTHORS file
198 at the root of this distribution (or repository). The canonical source
199 of per-line authorship is the git repository history itself.
200
202 Copyright (c) 2005 by mst, castaway, ribasushi, and other DBIx::Class
203 "AUTHORS" as listed above and in AUTHORS.
204 This library is free software and may be distributed under the same
206 terms as perl5 itself. See LICENSE for the complete licensing terms.
207perl v5.32.1 2021-01-27 DBIx::Class(3)